1. Field of the Invention
The present invention relates to a member adjacent to an automotive engine, as an engine cover such as an engine head cover and an oil pan and an air cleaner, which is capable of decreasing noises due to engine operations.
2. Description of the Prior Art
There are many parts adjacent to an engine for a vehicle, which are likely to vibrate and cause noises due to vibrations transmitted from the engine.
For example, an air cleaner 1 hitherto used for an engine is shown in FIG. 1, which comprises a main metal casing 2 and a cover 3 to form a housing in which an annular filter element 4 and packings 5, 6 and 7 for urging supporting the element 4. The cover 3 is secured by means of a threaded rod and a wing nut 9 through a packing 8 to the main casing 2 which is in turn fixed to a carburetor (not shown) of the engine through an insulator 10 by means of a clamp 11 and a bolt 12.
With such an air cleaner hitherto used, the main casing 2 and cover 3 are likely to transmit vibrations and formed parts of metal (plates) having low damping capacities, so that vibrations of the engine are transmitted from the carburetor to the air cleaner 1 to vibrate the main casing 2 and cover 3 so as to cause noises.
In general, moreover, a limited engine room does not provide a space sufficient to meet a required volume of the air cleaner. Accordingly, a capacity of the air cleaner for absorbing noises caused by an air intake of the engine is too small to muffle the great noises.
A cylinder head cover for an automotive engine in prior art consists generally of an integral metal cover 21 having an oil filler hole 24 and a blow-by gas outlet 25 secured through an oil seal or gasket 23 to a cylinder head 22 by means of bolts 26 as shown in FIG. 2.
As the cylinder head cover and cylinder head are thus rapidly connected and the cylinder head cover itself is apt to transmit vibrations, vibrations are transmitted from the engine to whole over the cylinder head cover to cause it to violently vibrate, thereby forming a source of noises by the cylinder head cover itself. Such noises are remarkably greater than the noises occurred at moving valves of the engine and transmitted through the cylinder head cover and provided a large problem to be solved.
An oil pan 31 has been used as shown in FIG. 3. As shown in FIG. 4, the oil pan 31 includes a partially deeper portion to form an oil reservoir 33 and is made of a thin steel sheet in consideration of light weight and heat dissipation. The oil pan 31 is rigidly fixed at its upper peripheries to lower peripheries of a skirt 32a of a cylinder block 32 through sealing materials 37 in an oil-tight manner as shown in FIG. 3.
The oil pan 31 thus mounted is likely to vibrate in directions of arrows 36 because of vibrations of the skirt 32a having a relatively low rigidity as shown in phantom lines 35 due to vibrations of a bearing cap portion 34 of the cylinder block 32. Such vibrations of the oil pan 31 cause noises which are part of the noises of the engine dissipating out of the engine room.